Flutter Interview Questions and Answers

Ques 1. What is Flutter?

Flutter is an open-source UI software development toolkit created by Google. It is used to develop natively compiled applications for mobile, web, and desktop from a single codebase.

Example:

import 'package:flutter/material.dart';
void main() => runApp(MyApp());

Ques 2. What is the 'setState' method in Flutter used for?

'setState' is a method in the 'State' class of Flutter. It is used to rebuild the widget tree and schedule a rebuild of the user interface when the internal state of the widget changes.

Example:

void _incrementCounter() {
  setState(() {
    _counter++;
  });
}

Ques 3. Explain the concept of 'Hot Reload' in Flutter.

'Hot Reload' is a feature in Flutter that allows developers to update the code while the app is running. It helps in quickly experimenting with the UI and fixing bugs without restarting the entire application.

Example:

void main() {
  runApp(MyApp());
}

Ques 4. What is the purpose of the 'Flutter Inspector'?

The 'Flutter Inspector' is a tool that allows developers to visualize and explore the widget tree, inspect widget properties, and understand the structure of a Flutter application during development.

Ques 5. Explain the concept of 'Flutter Widgets.'

Flutter widgets are the basic building blocks of a Flutter application. They are used to create the UI elements of the app. Widgets can be either stateful or stateless, and they are composed to build the overall UI.

Example:

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Text('Hello, Flutter!');
  }
}

Ques 6. What is the 'MaterialApp' widget used for?

The 'MaterialApp' widget in Flutter is used to set up the material design for a Flutter application. It provides features like navigation, theming, and accessibility that are common in material design.

Example:

void main() {
  runApp(MaterialApp(
    home: MyHomePage(),
  ));
}

Ques 7. What is the 'Pubspec.yaml' file in Flutter?

The 'Pubspec.yaml' file is a configuration file in Flutter projects that defines the metadata, dependencies, and other settings for the project. It is used by the 'pub' tool to manage project dependencies.

Example:

name: my_flutter_app
dependencies:
  flutter:
    sdk: flutter

Ques 8. Explain the concept of 'Splash Screen' in Flutter.

A 'Splash Screen' in Flutter is an introductory screen that appears when the app is launched. It is used to display branding, loading indicators, or perform initial setup before transitioning to the main application screen.

Ques 9. What is the 'BuildContext' in Flutter used for?

The 'BuildContext' is an object that represents the location of a widget within the widget tree. It is required for various operations, such as building other widgets, navigating to a new screen, and accessing theme data.

Example:

Widget build(BuildContext context) {
  return Container();
}

Ques 10. Explain the role of the 'main.dart' file in a Flutter project.

The 'main.dart' file is the entry point of a Flutter application. It contains the 'main' function, which is the starting point of the app. This file is responsible for creating and running the main application widget.

Example:

void main() {
  runApp(MyApp());
}